Are There Any Products or Procedures That Can Whiten Crowns?

There are no whitening products that can whiten crowns.  If you have a crown and get your teeth whitened you would need to replace your current crown.

The best way to whiten a crown is to replace the crown with a crown made in a lighter shade.  This is why it can be helpful to ask yourself if you like the color of your teeth before getting a crown done.  If you'd like to have whiter teeth, it's usually better to whiten them and then get any restorative work done.  Then when you go to shade match for your crown, for example, it will be more accurately matched to the lighter color of your whitened teeth.  

Hi:If your crowns are stained due to drinking tea, coffee or smoking, then Oral Essentials Whitening strips can help.  However, if you don’t like the color of your crowns, then they have to be replaced with a new one.Best,Dr. Maddahi

Kitty, thank you for your great question. The best procedure I know of to whiten crowns is to change them. In case crowns were done recently and there is nothing wrong with them except esthetically, a second option is to place Lumineers/veners over them. That's ok in some caes.

Porcelain crowns can not be whitened.  If the crown shows when you smile and the shade is really bothering you, then you may want to consider replacing the crown.  Best, Dr. Elizabeth Jahanian

There really is no way to whiten crowns in the mouth. The systems used to whiten teeth only work on tooth structure, not crowns, veneers, onlays, etc. The only way to whiten them is to replace them.

"Can I whiten my crowns?" is one of the most frequently asked questions in cosmetic dentistry. Teeth whitening has become one of the most popular and successful procedures. It can be accomplished in under an hour; it is relatively inexpensive and makes a big difference for people who want to brighten up their smiles. It would be wonderful to be able to do the same thing for crowns.
The average shade of white teeth in America keeps getting whiter every year and what was once considered a nornmal healthy color is now perceived as being too yellow. Although many people can have great success with whitening, the notable exceptions are previous dental work and tetracycline stains. The best solution in these cases is to replace the dental work or cover the stains with veneers. Porcelain is very color stable and will not change for the life of the teeth. In the case of one or two crowns dictating the color of the rest of the teeth we recommend whitening the dark teeth and then replacing the crowns to match the new brighter color.

Many people have asked this same question. Unfortunately there is nothing reasonable that can be done. The porcelain is very color stable, and doesn't respond to anything that can be placed in the mouth. You could however, reduce the porcelain on the crown and bond a new piece of porcelain to the existing crown. This can change the tooth, but will usually result in the same fee as simply replacing the crown. If you have a single crown that is lighter than the adjacent teeth, you could try whitening those teeth and see if that helps.
That is why I spend a lot of time before I do a porcelain restoration trying to make sure the patient is very happy with the present color of their teeth, because that is what we will match them to.

One of the benefits to modern dentistry is color stability. Smile makeovers, where a new color is chosen, satisfy for a long time since the colors don't degrade over time. This same "benefit" can be a problem in some situations.
If a single crown was placed and later the teeth were whitened, the crown that matched will no longer blend in. Same with fillings. Before teeth are whitened, people should be informed that dental restorations would need to be replaced/upgraded.
If you have a crown that is not the color that you would like it to be, it must be replaced.